feat: allow customize main menu via white labeling

Author: asvishnyakov

client-app/core/api/graphql/fragments/whiteLabelingFields.graphql

@@ -9,6 +9,16 @@ fragment whiteLabelingFields on WhiteLabelingSettingsType {
     sizes
     href
   }
+  mainMenuLinks {
+    title
+    url
+    priority
+    childItems {
+      title
+      url
+      priority
+    }
+  }
   footerLinks {
     title
     url